Differential-microphone repeater.



J. JJGOMER. DIFFERENTIAL MICROPHONE REPEATBR APPLICATION FILED 00124, IQlO.

Patented Jan..'14,,.1913.

render the said repeater especially adapted for service in loud speaking systems or UNITED STATES PATENT OFFICE.

JOHN J. COMER, or cHrcAeo, ILLINOIS,

ASSIGNOR TO AUTOMATIC ENUiIorATon.

. COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS DIFFERENTIAL- MICROPHONE REPEATER;

Specification of Letters Patent. 1 Patnted Jan. 14, 1913.

Application filed ctober 24. 1910. Serial No. 588,791.

To all Quiz-omit mo concern Be it known that I, JOHN J. Conan, a citizen of the United States of America,

and resident of Chicago, Cook county,

, which operates a differential microphone.

' heavy currents. 1

The impulses are thus'repeated by the mi crophone in another circuit.

'. Generally stated, the ob ect of my invention is'to provide a simple and highly efiicient form or construction of microphone repeater having provisions for accurate adv justment thereof to insure good results and other similar systems requiring the use of A special object is to provide an arrangement whereby a variable leverage may be effectively employed for changing vor regulating the amplitude of .vibration of the microphone repeater. 1

Another object is to provide an improved arrangement whereby'theair gap between themagnet and its, armature may be easily and accurately adjusted" or regulated to insure the highest degree of -eiiiciency of the repeater for all purposes and under all con- ,ditions\of use.

- Another object is to provide a construe .tion of. difierentialmicrophone repeater.

that will insure the'transmission of repeated impulses of a, character tending to insure greater clearness of enunciation and purity of;tone than heretofore.

To the foregoing and other useful ends ,invention consists in matters. hereinafter more fully set forthand claimed.

In the accompanying drawmgseFigure 1 is a longitudinal section of a :-differential.-

' which latter is secured to the plate 0., said julcrum being in the form of a hollow-screw microphone-repeater embodying the. principles of m inyention. Fig. 2 1s acrosssection onh'rie 22;in:F1g.' 1:; Figj3 is a. cross-section f'on line 3' -.-3 in Fig. 1. Fig. 4

a .front. end 'yiew of 'th'esaid repeater.

Fig.5 is. a rearend-viewpf said repeater. Fig. 6'iS.8.fYl eW1 O0k 1I1g downv on the reescaping.

peaterfshown in 1, with the casing thereof removed. Fig. 7 is a side view of the structure shown in Fig. 6. Fig; 8 is an enlarged section of the forward port-i011 of the repeater, similar to Fig. 1, but showing the rear portion broken away. i

thus illustrated, my inveption comprises a permanent magnetA, one pole of which is provided with a core or pole-piece a haying a coi a. An armature a is supported by a shoulder a on the pole' a" of the permanent magnet and is vibrated by the electrical impulses received in the coil a. A front plate B is secured by arms I) to the said permanent magnet. The said front plate has an opening 11 therein which is covered by, the differential microphone C that' is secured 'to the face 'ofsaid plate.

or other suitable material, and a pair of "carbon disks 0 and a? that close-the open ends of said ring and serve aselectrodes.

The mica disks 0? andc are applied to the outer surfaces ofthe said carbon disks, to.

cover the same and serve as insulation: but the metal disks 0 and e are interposed be tween said electrodes and the mica disksto serve as. terminals forthe microphone. A metal plate 0 is employed to cover the outer surface of the mica disk 0 the entire structure thus builtup beingheld together and upon'the front 'of the plate B ,by means of screws 0 The front and back walls of the m crophone :box' have. openings 0 and 6 therein to allow the stem 0 --to pass through the box A movable electrode-c is secured.

This microphone comprises a ring 0 of lava 9 upon said stem and disposed between the:

two stationary electrodes 0 and '0 A filling of granular carbon 0" is introduced through the bole o in'the top of the ring toserve' as the variable resistance in the usualand well known manner. The difi'er ,ent openings in the box can be filled withflufi'y asbestos to prevent the carbon from a The armature a is connected with the endof the stem" 0 and thereby operates the electrode 0 I A fulcrum D is mounted in the support d,

which canbe adjusted up and down in said support. The lever E is inserted downward through the screw or fulcrum'Dand has'a head 'E that keeps-it from falling through [and are-- m vided with'a spring f having a slot 7" engaged by the lower end of said lever. A 5

forward end provided with an eye (2 through which the lever E passes. The leverage is varied by raising'and' lowering the fulcrum D, as tli'is changes the distance between the fulcrum and the point at which the lever receives the power. After the eye 6 and the Q15, which latter hold the electrode 0' .he stem 0, are adjusted to bring about rough adjustment of the parts, the ful- D is then adjus ed to get the proper spring 7' and the condition geneiially. Then the screw f 15 ad usted to give the right ten sion and regulate the air gap. In this way a very perfect and satisfactory adjustment can be obtained.

A set-screw (Z is inserted through the side of the support (Z and engages the fulcrum l) to'hold the same in position after it has been adjusted. Any suitable. circuit arrangement can be employed for the microphone. .In such circuit arrangement the impulses received in the magnet will be repeated by themicrophone C, in the usual manner.

A repeater of this kind can be. used. for

lc 11d talking systems, and will 'carryheavy currents, as the structure of theinicrophone including the mica insulation will not be affected injuriously heat. It is simple and is, I find, a very satisfactory and highly eflicient form of microphone repeater.

What I claim as my invention is:

1. In a repeater, a difterential microphone, a magnet foroperating said microphone, a spring, means including a lever for connecting the spring with the magnet,

means for regulating the tension of said spring, and means for varying the leverage.

2. in a' repeater, a differential microphone, a magnet having an armature for operating said microphone, a springtor ret-racting the said armature, and means for adjust ng the said spring to regulate the air gap of said armature.

In a repeater, a ditferential microphone, a. magnet having an armature for .operating said microphone, a spring for retracting the armature, a lever through which the armature overcomes the tension of said spring, an It means fo varving the leverage. t In a repeater, a ditl 'erent-ial In crophone, a magnet" having an ari'nature for operating said microphone,v a spring for retracting the armaturc a lever through which said armat re overcomes the tension of said spring, a fulcrum for said lever, and means for varying the leverage by changing the distance between the fUlClul?" and the point eve'ra'ge', depending upon the stiffness of the i where th lever receives the power from said armature.

5. In a repeater, a differential microphone, a magnet havingan armature for operating said microphone, a spring for retracting said armature, a lever by which the iarmature overcomes the tension of said spring, and a fulcrum for said lever, said verage connection between and spring. I I

i. In a repeater, a microphone, a magnet.

said armature crophone located on one side thereof, a spring for retracting said armature located on the other side thereof, and means for adjusting said spring and armature toregulate the air gap of the latter.

8. In a. repeater, a differential micro-, phone, a magnet located upon one side thereof fcroperating the same, a spring located ,upon the opposite side of said microphone, and means includinga lever for connecting said spring with the armature of said magnet. I

' In a repeater, a. differential micro spring, and means including a stem passing through said microphone and carrying a movable electrode for connecting said spring with the armature of said magnet.

, 10; In a' repeater, a differential microphone, a magnet located upon one side of said microphone for operatingt-hesame, a spring located upon the opposite side of said microphone, and means'including a stem passing through said microphone and carrying a movable elect-rode for connecting said spring with thelarmature of said magnet-.

11. In a repeater, a differential microphone, a magnet located upon one sidc of said microphone for operating the same, a spring located upon the opposite side of said microphone, a level connected tosaid spring, and a stem connectedwith' said lever and the armature of said magnet with sald spring.

12. In a repeater, a-difi'erential microphone, a magnet located upon one side of said microphone for operating the same, a spring located upon the opposite side of said microphone, a lever connected to said spring, a stem connected with said lever andthe armature of said magnet for connecting the, armature of said magnet with said spring, and an adjustable fulcrum for said lever for varying the leverage; l

13. In a repeater, a difier'en'tial microtulcrum being adjustable to change the leon the other side thereof, and a variable 1chaving an armature for operating said mi-,

phone, a. magnet for operating the same, a.

armature of'said magnet for connecting the phone and a magnet for operating thesame,

. 1 L In a repeater, a differential microphone and a magnet for operating the same, a stem passing through. said microphone and carrying a movable electrodefa' connection at one end of said stem'to' the-armature of said -magnet, a. level extending at right angles to said stem, :1 connection from the opposite end'of said stem to said lever, a spring connected with oneend of said lever, and an.adjustable fulcrum for the opposite end of said lever whereby the leverage may be varied.

Signed by me at Chicago, Illinois, this 17thday of October, 1910.

' JOHN J. COMER. Witnesses:

H. LEWIS, E. H.- CLEGG. 

